THE BUTTERFLY VIVARIUM. 15 



able space. At the sides and back, the Vivarium is 

 to be of zinc, or glazed tiles, or slate, up to the 

 height of the joint just above the water-level, which 

 is shown in the front view. And, at this joint, the 

 whole of the upper part, or cover, of the Vivarium 

 is intended to lift off, for the purpose of general 

 cleaning, ventilating, etc., at proper opportunities, 

 when none of the insects are in a flying state. The 

 upper portion will be made to fit tightly to the lower, 

 by sinking into a deep groove, extending round the 

 whole joint. At the sides of the structure, joining 

 both back and front columns, a broad strip of per- 

 forated zinc will be attached, for ventilation, which 

 will form the frame-work to a glass-door, affording 

 easy access to all parts of the Vivarium, and entirely 

 occupying the rest of the space above the solid zinc 

 or tile- work, which will reach up to the joint, as 

 before stated. The lower part of the glass-door 

 will, therefore, be on a level with the surface of the 

 land arrangements, and will reach to the top of the 

 square portion of the frame, from which the roof 

 springs. The opposite side will be the same, except 

 that the glass portion need not be made to open, 

 as another door would scarcely be necessary ; and I 

 may remark here, that the little gallery at the crown 

 of the roof is also of perforated zinc. 



